[The text below is a modified transcript of this video.]

5) Couch Potatoes on Mars

When you're sending a manned mission to Mars, you need to plan for every aspect of the trip; including how to get a good night's rest. A simulated Mars mission has shown the importance of balancing activity with sleep to stay on top of your game.

For 17 months, a six-person international crew lived in confined isolation, a situation similar to the one Mars pioneers can expect. Throughout the simulation, researchers recorded each individual's light exposure, sleep time and quality, activity levels, and workload.

As the mission progressed, the crew slowly transformed into couch potatoes. They moved less during waking hours and spent more time lying still and sleeping. And most crew members slept poorly, which affected the quality of their work.

In order for the members of a Mars mission to perform their best, the researchers suggest habitats and work schedules that mimic conditions back on Earth -- not the conditions where you sink into the sofa with a bag of chips.

The study was published in the early edition of this week's Proceedings of the National Academy of Sciences.

4) 100 Billion Exoplanets

Astronomers now estimate our galaxy houses at least 100 billion planets.

They figured this out by training the Kepler space telescope on one particular star system, Kepler-32. This system features a star classified as an M dwarf, which is cooler and smaller than our own sun, but much more common. About 70 percent of the stars in the Milky Way are M dwarfs.

Although Kepler-32 is a fairly typical system, its orientation is special—it faces the Kepler telescope in a way that lets us see its five planets passing in front of their star. This position helped Caltech researchers discover the sizes and orbits of the planets in Kepler-32.

The astronomers were hoping to find out how Kepler-32’s planets formed. But the orientation of the system also let them calculate the probability that other stars house planets. They estimate that each M dwarf star in the Milky Way has at least one and possibly two planets in close orbit, which means our galaxy is filled with 100 to 200 billion planets.

3) Amateur Discovery

Sure, 100 billion is a big number. But it’s only an estimate, not a definite discovery. Amateur volunteers have found the signatures of 43 actual planets. And15 of them sit in habitable zones, the regions around stars where the temperature is just right for life-enabling liquid water.

This discovery comes courtesy of the Planet Hunters project, where amateur astronomers comb through public data from the Kepler telescope. This is the same telescope that gave us that estimate of 100 billion planets.

Of the 15 candidates they discovered in habitable zones, only one was confirmed through follow-up observations at Hawaii's Keck telescope. Dubbed Ph2 b, this planet is the size of Jupiter and orbits a sun similar to our own. If it also has moons like Jupiter's, they might be able to join the list of potentially habitable worlds.

And as amateurs and scientists keep hunting planets, this list will just keep growing.

2) Asteroid Flyby

Did you hear the Earth was buzzed by an asteroid yesterday? The asteroid Apophis flew by at a distance of 14.5 million kilometers. That's roughly 30 times the distance from the Earth to the moon. Good thing, because it’s a huge asteroid, with a diameter close to the height of the Eiffel Tower.

Disaster averted! We can all breathe a collective sigh of relief...right?

Well, not until after February 15th. That’s when a smaller asteroid--only a football field across--will pass closer to Earth, much closer. The asteroid will only miss us by 35,000 km. That's well inside the orbit of the moon and even within range of some communications satellites.

Fortunately, astronomers predict the asteroid, named 2012 DA14, won’t hit Earth. Let me repeat: There's no chance it will hit the Earth! But assuming it did, we'd be in for some serious mayhem. An impact would generate 120 times the energy of the nuclear bomb dropped on Hiroshima during World War II.

But in all likelihood 2012 DA14 will pass quietly by Earth, just like Apophis, and continue its orbit around the sun.

1) A Moon for the Moon

Why would scientists want to give our moon--a moon? Well, NASA wants to harness an asteroid and place it in orbit around our largest satellite.

The proposed mission would send a spacecraft to snag a 7-meter-wide space rock. The rock would be stored in a bag and transported to the moon. There, the asteroid would be carefully released into orbit.

According to Keck Institute scientists, capturing and delivering the asteroid could take six to ten years to complete and cost around $2.6 billion.

The scientists say this project would move us one step closer to a manned asteroid mission in 2025 and a Mars mission by 2030. The astronauts wouldn’t have to travel very far to visit an asteroid or expose themselves to the harmful space radiation that exists outside of Earth’s magnetic field. It would also make asteroid samples readily available for study and extraction of precious metals.

Does the moon deserve a moon of its very own or are there better ways NASA could spend its money?

- Portions of the script above written by Sophie Bushwick, Eric R. Olson & Isha Soni